1. Field of the Invention
The present invention relates to a photoelectric conversion apparatus and an image pickup system, and more particularly to a photoelectric conversion apparatus and an image pickup system both of which include a plurality of light receiving portions arrange on a semiconductor substrate, an antireflective film formed above the light receiving portions with an insulation film put between them, and color filter layers of a plurality of colors formed on the antireflective film.
2. Description of Related Art
As a solid state image pickup device, a charge coupled device (CCD) type photoelectric conversion element has conventionally been used in many cases. However, a complementary metal oxide semiconductor (CMOS) type photoelectric conversion element has been reconsidered recently, and a trend of commercialization of product of the CMOS type photoelectric conversion element has been generated owing to the merits of the CMOS type photoelectric conversion element such as its power consumption lower than that of the CCD type photoelectric conversion element, its operability of the use of a single power supply, and its producibility of its light receiving portion and its peripheral circuits by the same CMOS process, which makes it easy to integrate the CMOS type photoelectric conversion element.
As the configuration of a conventional solid state image pickup device, for example, there is one proposed in Japanese Patent Application Laid-Open No. 2000-12822. An example of the pixel configuration of the disclosed metal oxide semiconductor (MOS) type solid state image pickup device is shown in FIG. 9. The MOS type solid state image pickup device shown in FIG. 9 is a solid state image pickup device adopting a method in which signal charges are transferred from light receiving portions to detection portions to output potential changes generated by the detection portions. Each pixel of the MOS type solid state image pickup device is composed of a light receiving portion and four transistors of a transfer transistor, an amplifying transistor, a reset transistor and a selection transistor. The transfer transistor is a MOS transistor composed of a light receiving portion 43, a detection portion 44a, both of which are n type diffusion regions formed in a p type silicon substrate 40, and a transfer gate electrode 42 formed above the silicon substrate between both the regions with an insulation film 41 put between the transfer gate electrode 42 and the silicon substrate. The transfer transistor uses the light receiving portion 43 and the detection portion 44a as its source and its drain, respectively.
An antireflective film 45a is formed above the light receiving portion 43 with the insulation film 41 put between them. In such a configuration, by the interference caused by the antireflective film 45a (silicon nitride film) and the insulation film (silicon oxide film) 41, and by the interference caused by the films including the above-mentioned two films and an interlayer insulation film formed above the two films, the reflection of light at an interface between the silicon and the silicon oxide film is suppressed to enable the sensitivity to be improved. A reference numeral 46a denotes an insulation film (silicon oxide film); a reference numeral 44b denotes an electric field relief region; reference numerals 45b and 46b denote side insulation films (silicon nitride film and silicon oxide film).